Unexplored Territory #105 - How do I enable vSAN ESA Global Deduplication in 9.0?
Oct 19, 2025
Pete Koehler, a vSAN expert, dives deep into the newly released vSAN ESA global deduplication feature. He explains the advantages of this approach, including its cluster-wide deduplication domain and how it minimizes VM performance impact. The discussion reveals the surprising requirements, like needing at least three hosts and 25GbE networking. Koehler also addresses the limitations, noting that stretched clusters and data-at-rest encryption aren't supported yet. Finally, he shares how customers can request access to this limited release.
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Cluster-Wide Deduplication Delivers Major Savings
- vSAN ESA expands deduplication scope from disk-group level to the entire cluster, enabling much higher space savings.
- Post-process global dedupe finds duplicates across hosts for far greater efficiency than OSA's disk-group inline approach.
OSA's Dedupe Limits Drove ESA Redesign
- OSA's deduplication was disk-group scoped and inline, which limited savings and could impact performance under load.
- ESA rethinks the approach to overcome those historical limitations.
Post-Process Design Protects VM Performance
- vSAN ESA uses a post-processing deduplication method to avoid impacting VM performance during writes.
- The system runs intelligently in the background and self-manages dedupe timing and load.